P0533
P0533-A/C SENDING UNIT VOLTS TOO HIGHP0553 - A/C Sending Unit Volts Too High:
WHEN MONITORED
With the ignition on and battery voltage greater than 10.4 volts.
SET CONDITION
The circuit voltage to the ECM is above a calibrated threshold for a certain period of time.
POSSIBLE CAUSES
- Other DTC's
- A/C pressure sensor
- (C918) Signal circuit shorted to battery positive
- (F855) 5-Volt supply circuit shorted to battery positive
- (K916) Return circuit open from ECM harness connector to A/C harness connector
- ECM
- Intermittent condition
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. OTHER DTC'S
Turn the ignition on.
With the scan tool, read DTCs.
Q: Are other DTC's present?
YES: Repair other DTC's first. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 2
2. HARNESS OPEN
Turn the ignition off.
Disconnect the A/C pressure sending unit harness connector.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (F855) 5-volt supply circuit and (K916) return circuit of the sensor harness connector.
Q: Is the voltage between 4.5 and 5.5 volts?
YES: Go To 3
NO: Go To 4
3. A/C PRESSURE SENSOR
While monitoring scan tool, use a jumper wire to connect the (K916) return circuit to the (C918) signal circuit at the sensor harness connector.
Q: Did P0532 set?
YES: Replace the A/C pressure sensor. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4
4. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO BATTERY NEGATIVE
Turn the ignition off.
Disconnect the ECM harness connectors.
Check connectors - Clean/repair as necessary.
Measure the voltage between the (F855) 5-volt supply circuit at the harness connector and battery negative.
Q: Is the voltage less than 1 volt?
YES: Go To 5
NO: Repair the (F855) 5-volt supply circuit shorted to the battery negative. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
5. (C918) SIGNAL CIRCUIT SHORTED TO BATTERY NEGATIVE
Measure the voltage between the (C918) signal circuit at the harness connector and battery negative.
Q: Is the voltage less than 1 volt?
YES: Go To 6
NO: Repair the (C918) signal circuit shorted to the battery negative. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
6. (K916) RETURN CIRCUIT OPEN FROM ECM HARNESS CONNECTOR TO A/C HARNESS CONNECTOR
Measure the resistance of the (K916) return circuit between the sensor harness connector and the ECM harness connector.
Q: Is the resistance less than 10 Ohms?
YES: Go To 7
NO: Repair the open (K916) return circuit. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
7. ECM
Reconnect the ECM harness connectors.
Turn the ignition on.
While monitoring scan tool, use a jumper wire to connect the (K916) return circuit with the (C918) signal circuit at the sensor harness connector.
Q: Did DTC P0532 set?
YES: Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
NO: Replace the ECM. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1